An Iranian prosecutor today demanded the "full punishment" for a senior reformist figure in the latest mass trial of government opponents and protesters – potentially meaning the death penalty.

The Iranian state cast Saeed Hajjarian, a key figure in the pro-democracy reform programme under the former president Mohammad Khatami, as the main villain at the trial.

A prosecutor read out a long list of charges against him and other defendants, including acting against national security, fomenting unrest, having contacts with British intelligence and insulting Iran's supreme leader, Ayatollah Ali Khamenei.

The prosecutor called for the "full punishment" to be brought against Hajjarian, although officials have not clarified what that could entail.

In theory it could mean a death sentence, but that would risk a public backlash because he is revered as a hero of the reform movement.

Hajjarian was shot in the head from close range in an assassination attempt in 2000, leaving him partially paralysed. He uses a wheelchair and has difficulty speaking.

Two people supported him on his way into the courtroom, carrying him by the arms, the state IRNA news agency said.

Hajjarian identified himself to the court before asking another defendant, Saeed Shariati, to read a text of his confessions on his behalf because of his inability to speak fluently.

"I've committed grave mistakes by offering incorrect analysis during the election ... I apologise to the dear Iranian nation because of my incorrect analysis that was the basis for many wrong actions," IRNA reported the text as saying.

The opposition has said defendants have been forced to make confessions, denouncing the proceedings as a "show trial" aimed at smearing the opposition movement in the public eye.

State TV showed the accused sitting in rows in the courtroom, wearing prison clothes and slippers, listening as charges were read out.

IRNA said Hajjarian had announced his resignation from Mosharekat, Iran's leading reformist party.

It said a prosecutor had called for Mosharekat and another reformist party to be dissolved.

Mir Hossein Mousavi, the leading reformist candidate in the June election, said confessions by some of the accused in past trials had been made under duress.

Others who appeared in court today included the former deputy interior minister Mostafa Tajzadeh, the former deputy foreign minister Mohsen Aminzadeh and Abdollah Ramezanzadeh, an ex-government spokesman, all prominent reformists.

The defendants are charged with fomenting riots and attempting to overthrow the ruling system with a "velvet revolution" similar to uprisings in eastern Europe.

Hundreds of protesters, opposition politicians and activists have been arrested in the crackdown on the opposition, which accuses Mahmoud Ahmadinejad of stealing the election from Mousavi.